A conventional vehicle shown in Patent Literature 1 has a pair of left and right rear arms suspended via a shock absorber on a vehicle body, with one end portion of each rear arm being used to support a rear wheel and the other end portion of each rear arm being coupled to the vehicle body. The one end portion of each rear arm can be individually moved in a vertical direction. When the vehicle turns, the outside rear wheel with respect to the turning direction is given larger driving force than the inside rear wheel. This causes a difference in the driving force between the left and the right rear wheels. This difference makes the rear arm on the outer side with respect to the turning direction move more in a vertical direction than the rear arm on the inner side with respect to the turning direction. Accordingly, the vehicle body is tilted inwardly with respect to the turning direction. This makes the vehicle's turning ability better.
In addition, in a conventional vehicle shown in Patent Literature 2, a single swing arm 44 extends forwardly of a vehicle body frame 41. A rear end portion of this swing arm 44 is rotatably mounted about a vehicle widthwise shaft to a front end portion of the vehicle body frame 41. A king pin 73 is attached to a front portion of this swing arm 44. A cross beam 64 extending in a vehicle-widthwise direction is rotatably mounted about the axis of the king pin 73. A pair of left and right front wheels (13 and 13) are rotatably mounted to both ends of the cross beam 64. Such a configuration allows each front wheel 13 to be suspended using the common swing arm 44. Accordingly, this structure is simpler than the structure in which each front wheel 13 is suspended using a different swing arm. Also, such a configuration can be achieved using a smaller number of components.